Tag Archives: plywood boats

Post navigation

OK, right off the top, here, I’m going to admit that this design study was instigated originally after looking at an article on the Jim Michalak design, the Harmonica. The more I studied the photos in the story, the more it flashed on me that this boat would look very similar to a typical pickup truck, cab-over camper if it were flipped upside down.

Then, in one of those absolutely weird, Popular Mechanics, moments we all get after too many years in the garage twiddling with stuff, it hit me. The Harmonica design of Jim’s could actually serve as a jumping-off point to draw-up a really utilitarian camper/boat that a retiree could use all over the country while he lived in the camper as his home on wheels. I’m kinda poking my finger in the eye of the guys at Pop Mechanics because all my life they constantly ran all these wild and crazy inventions that really stirred my imagination in a big way. The Flippin’ Boat is right up their alley.

I’m not so sure the little woman in this retiree’s life would actually go for having a 1960’s inspired, Tomorrowland boat on their camper. Nor was I convinced that there wouldn’t be hell to pay for even suggesting the potential over Mac and Cheese with weenies. But, the idea looked kinda fun to me anyway, so I started fooling with a few possible lines for the boat that I hoped would conquer Route 66 one day.

The first thing would be to settle on a hull shape that would work well in a lot of conditions and could carry the load of a superstructure that would emerge from the camper box that goes in the bed of a truck. I wanted a cab-over design so that the hull could be fairly long when compared to the height of the camper form.

I settled on the moderate vee hull without a spray chine to keep things simple to build. I like the way moderate vee handle in a lot of widely varied conditions without pounding when things get rough. The moderate depth of the vee means that this boat can be taken into reasonably shallow water without problems. That will make it easier to anchor, take stuff ashore while wading and they are pretty easy to build. The form also presents a surprisingly good aerodynamic shape to the wind at highway speeds.

Keep in mind that this boat has to work upside down and right side up, or it becomes a fairly stupid exercise in a real hurry. A crappy looking boat would never appeal to the guys at Popular Mechanics, even if it did work decently.

I wanted windows so the cabin area would be airy inside. This is a pretty boxy shape, so it can’t look like a shed that has been plunked down on the hull.

What about the utility of the design? You can see that the Flippin’ Boat has a nice front porch area so that you can fish, or sit in the afternoon’s fading sunlight with a cold one in hand or set-up BBQ. There’s another porch on the stern end of the hull for fuel and engine business, as well as a space for letting your flatulent uncle have a little privacy.

The main cabin is fashioned to follow the form as provided by the bed of the truck. In this case, it works out that there is a wonderful, stacked sensation, of a multi-level house with lots of big bright windows to let in the light and the wonderful views of the lake or river on which the boat might be anchored.

I gave all the boxy corners a radius turn to soften the look of the cabin once launched. There isn’t a whole lot you can do to a basically boxy form that fits in the bed of a pickup for stability. This change made a world of difference and really improved the overall looks of the design.

One of the big concerns for me was how to make furniture for the camper that would also work for the boat. Lots of stuff is sort of no-brainer like the boat flips and the bed becomes… the couch/bed when you put the cushion on the other side of the same structure. But what about tables and cabinets and stuff like that? I don’t now too many folks who would want their dish cabinet turned upside down and find it sitting near the floor of their boat.

I designed all the simple, wall mounted fixtures so that they were on swivels. As the camper is turned over to become a boat, the fixtures rotate around to their normal, right side up position and none of the interior contents are disturbed. Of course, this means that the placement has to make sense for both scenarios, but it turns out to be not such a big problem once I took a look at how it needed to work.

One other little item that deserves mention. There is a raised, cockpit-style coaming ring around the front porch area. This serves two purposes. As a camper, this coaming provides a more aerodynamic seal against the cab roof. I know it matters only a little in the grand scheme of things with such a big hulking structure sitting up there over the truck, but I like that the idea was addressed in the design. Second, in boat mode, the ring helps to deflect spray away from the front door of the house and the front porch, aiding in overall comfort while underway.

So, the big question is, “How do you get this Bad Dude flipped over and in the water?” That’s sort of important isn’t it? While I was goofing around trying to get my brain wrapped around the practical uses of pulleys, cables whiz-bang gadgets, etc. I stumbled upon a Swiss designed lift system that is being manufactured in Iowa by Stellar Industries that will lift fairly heavy items right out of a truck bed and deposit them on the ground in their intact, right-side-up orientation. They even show the retrieval of a jetski from a launching ramp as an example of the usefulness of their device. You can checkout their website here:http://www.xtralift.com/

When I saw that product, it dawned on me that I could then just roll the camper over with a couple of big curved wheel shapes mounted to the back end of the camper and inserted into preformed pockets to hold them fast. The hydraulic system already in the truck bed for the lift system would now serve a second duty. I’d only have to install a telescoping ram to lift the bow of the boat and at some point, gravity would do the rest, putting the boat on its hull in the water.

After a week on the water, retrieval of the boat to camper status is accomplished by means of a cable taken off a back bumper winch. The transom rotation wheels are installed once again. A Gin Pole is mounted to the top of the cabin and the cable goes up and over the Gin Pole to the bow. Reel in the cable and the bow lifts as if you were stepping a mast on a sailboat. Once near vertical, the telescoping ram re-attaches and the boat is gently returned to earth, resting on the lifting mechanism as a camper.

Of course there are all sorts of little maneuvers to make sure you don’t screw something up, such as removal of the Gin Pole before sitting the boat back in its lifting cradle; stuff like that which is too much written material for this article, but you get the idea.

The outboard is stored in the camper when not on the boat and the fuel is stashed under the camper in the cavity near the wheel wells in the truck bed. Sure, there’s lot’s of detail stuff to be worked out, but this is not a manufacturing description. It’s only a design study to examine feasibility.

Right now, the whole thing looks more than feasible to me and could progress to the next stage with a financing partner who had a bent for stuff like this. I’ve got the boat part of it covered and I’m pretty happy with the way the boat balances in the water, the stability of the hull form and its overall usefulness in a wide range of water conditions. No, it’s not meant to get up on a plane with the small outboard that will be easily moved around by the owner, but it will provide miles of comfortable cruising and get terrific fuel mileage as a payback for not being the fastest boat on the water.

This boat was designed to fit on any extracab/clubcab equipped, full-sized pickup with a long box. The truck should have a pretty decent engine due to seriously increased wind resistance and the battery and technical add-ons that one would suspect for a full-tilt trailering package. Stuff like tranny coolers, bigger brakes, ¾ ton minimum load capacity axle, oil coolers, bigger radiator, etc.

Yeah, the idea is a bit on the gimmicky side of things. But, so what. I’ve enjoyed the process of working out all the dual application issues (and there are a lot of them) as well as coming up with a nice aesthetically pleasing design that could actually work in the real world if someone cared to build it.

One final note: The name Flippin’ Boat should be pretty obvious as to how that came about. There is, however, one extra little sidebar piece of information to add a bit more to the business of the name selection. I live in Salt Lake City, Utah. A lot of folks in this community find it offensive to swear, so most of the conventional swear words that one would hear occasionally have been supplanted with euphemistic, non-swear words. Hell has become Heck and you probably guess what the equivalent for Flippin’ would be. I’m not of the predominant faith, but this is just my way of tipping the cap to the local culture in a fun manner. No offense intended to anyone.

A Modular System Approach to SOT Kayak Sailing, Paddling and Mirage Drive Propulsion

Sit-On-Top (SOT) kayaks are easy boats on which to learn to paddle. They have none of the “get in the coffin and you are about to drown” psychological identity that one finds in the Sit-Inside boats and they’re amazingly adaptable to a wide range of paddling activities. It also doesn’t hurt that they are pretty straightforward boats to rotomold, which makes them very cheap to produce in large numbers.

I didn’t envision just one boat for this niche in the home-built kayak market. Instead, it came to me that there would need to be at least three models that could address the wide-ranging styles of boating interests in this area of the kayak world. The result was a couple of very clean, SOT models at 14’ and 16’ called the Corona and the Back Bay, respectively. The third model was going to be called the Wahoo, as it was specifically designed for the folks who spend a lot of time fishing with their SOT’s. I’ll get to the Wahoo in the next article.

As a canoe and kayak sailor and a guy who had just been out for a test drive on the Hobie Adventure Island, which is based on their 16’ SOT Adventure model, I wanted to offer my own take on what makes for a truly fun and stylish, sailing SOT kayak. The result was that a fully integrated system of component parts was designed for the basic Back Bay. This modular approach allows the Back Bay to go sailing by simply adding a system of light-weight, easily built elements that quickly convert the SOT to a single aka sailing boat called the Scorpion, OR, to a double aka sailing boat with slightly larger ama volume, called the Doubloon. Of the two configurations, the Doubloon is most like the well-known and highly respected, Hobie Adventure Island.

The Corona and the Back Bay are virtually identical models, save for their respective lengths. For the purposes of this article, I’ll focus on the Back Bay version and all the potential add-on systems I’ve incorporated in the design.

THE BACK BAY SOT KAYAK

This boat is built in the S&G style of construction in 4mm marine ply with 6 oz. plain weave fiberglass set in epoxy on the inside and outside of the hull for full laminate sandwich strength. The build process uses external cradles as building supports, ensuring that the hull goes together with minimum hassle when handling the rather slender and longish hull panels. The boat is bulkheaded internally at three key points. These bulkheads create not only integrated strength in the design, but they also cleanly separate the hull cavity into four unique volumes for gear storage and watertight flotation.

The Back Bay can be configured with a large, open tankwell set aft of the cockpit, or built with a watertight, aft hatch cover for internal storage in a conventional kayak style.

The Scorpion variant is a Sit-On-Top design for fun sailing, paddling, or Mirage peddling… or all three, as the builder desires. There will be a design for a leeboard mount included in the plans for those who are going to build the boat for sailing. Having the aka gull wing form set well forward permits a full paddle swing arc. The aka beam connectives to the amas is split into a pair of mounting elements. I did this to make for a stronger, single beam mounting struture. With a single beam design, there is a tendency for the am to want to rotate around the beam, making for a very stressed component that could lead to early failure. By splitting the beam and spreading the mounting points, I have given the structure more resistance to this rotational force, making for a more rigid boat in use. This setup will allow the owner to power sail in light air with both the paddle and the sail providing thrust. With the leeboard swung down for sailing, the owner can do some “power sailing” and utilize the Mirage drive, as well as the sail, in light conditions. The Mirage is capable of boosting boat speed enough that it creates apparent wind over the sail, adding power where there really isn’t enough for sailing alone.

The amas are positioned to optimize capsize resistance when sailing off the wind. The amas do not touch the surface of the water at rest in stable trim and provide only minimal wetted surface drag when underway by paddle or peddle. As soon as the sail is loaded by the breeze, though, the ama on the lee side begins to immerse, firming-up the boat and resisting the heeling moments being generated.

The aft deck can be configured as a watertight hatch with full access to the aft sections of the hull, OR a large, diving tank well with self-draining ports. The cockpit is fitted with self-drain ports under the seat as well as forward, in addition to the daggerboard slot. There is a watertight deck plate just forward of the seat, between the knees of the sailor/paddler to provide secure storage for critical items that may be needed on a routine basis. The foredeck has a watertight hatch cover for bow storage needs.

The rig is a fully battened Dacron sail with two reef points and a multi-section, self-supporting mast which steps into a sealed mast socket in the hull. The mast and boom sections can be aluminum or carbon, as budget permits. The sail choice is open for the customer as long as it can be balanced with the fixed positions for the mast and dagger board. The Cunningham is run to the deck of the gull wing aka to keep the rig on the boat in the event of a capsize.

With 56-sq. ft. of sail on a 90-pound boat, this will be a decently speedy boat without being in over its head all the time in a stiff breeze. I suggest two reef points in the sail to allow for sailing in a wide variety of conditions.

This will be a wet boat at speed, yet there are no worries at all for flooding and sinking, save for a truly nasty trip over a reef that shreds the entire underside of the craft. The bow, cockpit and aft hull volumes are all independent, sealed compartments, as are the ama volumes.

Reentry from a swimming session will be easy with a simple, sling, or rope ladder much like those used by rock climbers, called etriers.

Sliding foot pedals in the cockpit control the rudder. The rudder flips-up when it encounters an underwater obstacle, or when beaching, returning, due to bungee tension to the deployed position once past the obstruction.

The boat is constructed in a multichine, marine plywood style with epoxy glass laminates inside and out in a stitch and glue style. Stainless T-Nuts are embedded in the hull deck surface from below to provide a secure set of mounting points for the aka wing. The amas are held in place on the aka tips by large bungees and a notched lock system. This system provides for quick setups on the beach.

You just fit the aka to the foredeck, insert four, 1/4″ threaded stainless screws with comfortable, knobbed grips and screw down the aka wing. The amas slip onto the ends of the aka and you lift the pair of 3/8″ bungees up and over two raised hooks on the aka ends to secure the ama in place. Simple, easily maintained and near foolproof in operation.

DOUBLOON SAILING SOT

The Doubloon is the second variation on the central SOT theme of this group of boats. In this design, I am looking to provide a more expansive utility application for the base, Back Bay SOT version. The Doubloon is essentially a solo craft and it carries the same, 56 sq. ft. sail, but the overall potential of the boat is expanded through the use of dual akas and full trampolines on both sides of the Back Bay hull. The rendering of the Doubloon shows a daggerboard inserted down through the Mirage Drive trunk, but in use, I would prefer to have the board mounted outside the Back Bay hull as a leeboard. Plans will be supplied with the leeboard solution.

The akas on the Doubloon are spaced to allow for a full paddle stroke with the boat setup as a trimaran. There are two sections of tubing that span the opening fore and aft between the akas from which the tramp is mounted. The trampolines are designed to roll-up on the outer tube section, much like a window shade and they are deployed by an endless loop of light halyard line. With the tramps fully deployed, the inner tube section lifts up and over a holding pin in the aka and the sailor applies as much tension to the tramp as he feels he needs by hauling-in the endless loop line and cleating it off. If a paddling session is desired, he simply pops the jam cleat and pulls the line to roll-up the tramp on the outer tube section. This procedure applies for both port and starboard tramps.

Like the Scorpion, the Doubloon can be built to utilize a Mirage drive in the center well and the need to roll-up the tramps for paddling is essentially negated, (though it is nice to have the option once in awhile as Mirage drives can be difficult to maneuver in tight places)

The aka beams are held to the deck of the Back Bay hull with the same, threaded knob strategy for quick setup and takedown times. Similarly, the amas are held to the aka ends with hefty bungee cords for the simplicity of use. There’s another, rather invisible, benefit to using the bungee cords for ama mounting. Because they are being held in place through a fairly dynamic hold-down system, the amas can move about, ever so slightly, while underway. This allows the amas to have some structural “give” and the result is that the banging and thrashing that is typically experienced by the ama, is somewhat dissipated through the flex of the joining system.

The design similarities to the Hobie Adventure Island are obvious. This boat, however, should be just a bit faster in the water, mostly because it will be much lighter than the rotomolded Hobie. For that same reason, it will also be easier to put it up on a roof rack for transport to the water and a lot easier on the back when you have to take it off the car to store it at home. The Doubloon configuration allows the sailor/paddler/peddler to bring along extra gear, which can be lashed to the tramps in waterproof bags. They can also take along kids, or perhaps someone special, who could lounge out on the tramp surface while lazily sailing along for a sunset cruise on a warm summer evening.

All in all, I think the Back Bay SOT should be a really fun boat to own for warm water/warm weather boating adventures. It has the capacity to carry enough gear for several days out on the water. When rigged with a sailing system of your choice, it can also cover some pretty good distances if the winds are favorable. Plans for this boat and all its variations will be available from this site and Duckworks Magazine.

Thin Water Tunnel Hull design

Recently, I put up an informative article on two, economy Jonboats; Swamper and Swamp King: http://lunadadesign.net/swamper-and-swamp-king/ Those boats were drawn to address a very simple and practical approach to a thin water, all-purpose utility skiff and there has been a very nice response from readers seeking plans.

Taking the Jonboat concept further, I got an email from a boating enthusiast asking if I had ever designed a tunnel hull boat along the lines of the Swamper. He indicated that he had seen a boat something like that which had been designed for very thin water work. The boat in question was a full 20’ in length and he felt that the size would be just too much for one guy to either pole around or man- handle in any kind of windy situation. So, he was asking if I had one like that about 16’ long.

It turned out that I did not, but weirdly enough, I had been tossing an idea around very much like his request for some time. He was kind enough to direct me to the www.bateau.com website where I could take a look at the fine design work of Jacques Mertens and his XF20. http://bateau.com/proddetail.php?prod=XF20#.VdpaH_lViko

To be completely candid, I felt that the XF20 was quite a nice boat in every respect except that I had a customer who was asking about one for his needs, which needed to be 4 feet shorter. I had already designed a full-tilt, 18’ vee hulled flats machine for fast runs across open, choppy bays and thin water poling sessions called The Flatsmonster.

So, I took many of the ideas I had in the Flatsmonster design and the Swamper series and combined them with the really nice elements of the XF20 to create the Blackwater 16.
Because of this choice of bottom shapes, this boat will be a lot more fun if you try to take it across a choppy body of water at speed. The forward vee shape of the hull will allow for faster speeds in open water as it will help to cut through the waves rather than bounce over them. As a swamper’s poling machine, it will excel in the narrow backwaters and thin mangrove estuaries where some really prize fish hang out, well out of reach of conventional fishing boats.

This is a pocket tunnel hulled boat with a wide stance that can support two fishermen and all their gear in very, very thin water. The hull has defined, 8 degree vee sections up front to help break some of the light chop one might find on backwater sessions in the late afternoon. The run aft from amidships is very nearly flat to allow the boat to plane easily with a very small outboard.

If you want to take this boat into the Bayou and hunt for a pig, you’ll find that the hull can carry a very sizeable load with ease. I can really see this design as perfect for a duck hunter. Just rig a short mast in the center of the hull and hang a camo net over the gunnels and you have room to spare underneath for your cooler, your gun selection and the battery powered TV with earphones.

I’m not going to go into the technical description of the pocket tunnel, as there is a wonderful paragraph on the functional aspects on the Bateau site. Needless to say, the tunnel allows the engine to be raised up higher than normal giving additional clearance in the water for the prop to run in shallow water.

This means you can go further into the creeks in your boat while using the engine. That translates to being able to stay out longer and come home later because of the additional speed over a poled boat in really shallow water. I figure nearly four additional inches of water depth before you’ll have to shut it down and paddle compared to a conventional Jonboat.

I suggest that you don’t exceed 30 hp for an outboard on this boat so that you can maximize the potential of the thin water capability. It’ll run surprisingly good with a 10-20-hp engine and in thin water and tight quarters, a lot of power would just go to waste, anyway. There’s a tendency to install too big an outboard on most recreational boats. I’m hoping that most folks recognize that a lighter, more efficient engine is actually better all around for 90% of all the boating work you will need to do.

Construction of the boat is in stitch and glue style with 3/8” hull bottom panels, deck, seat and fishing surfaces and ¼” plywood everywhere else save the transom. There is a lightweight framework truss in the hull beneath the deck to give the boat longitudinal strength. The suggested bench seats and forward fishing platform also serve as flotation chambers to keep the boat afloat in case it is swamped. The builders of this boat have the potential to build the interior out anyway they would like beyond the supplied bench seat design, but the more they add, the heavier the boat gets and that starts to take away the thin water capability of the design.

As shown in the illustrations, there is a midships frame and a continuous surface deck. Under the deck are two, full length stringers. These additions provide for a near bullet-proof hull with an added benefit. If the hull skin were to be holed from an unseen underwater obstacle, the flooding would be confined to the area of the damage as the compartments under the deck are sealed from one another to provide flotation integrity. Yes, the boat is a little heavier, but the payoff is in the enhanced safety, and hull rigidity if you decide to take it up to faster planing speeds.

This is an easy boat to build and it will provide hundreds of hours of enjoyment for the owner, especially after he customizes the interior to suit his favorite applications and fits-out the boat with all the trick goodies for his recreational passion.I suggest that the boat be built with epoxy taped seams inside at all joints with a full layer of epoxy glass on the outside of the hull. Prudent builders will add a layer (or two) of extra glass at all the sharper, hard corners to protect them from the inevitable banging a boat of this type will receive during use.

Plans will be available in the next month from Duckworks and will run USD$75. They include full-sized paper templates and detailed instructions regarding any of the stuff that is not straight forward, simple. There is also a suggested layout map for nesting the panels efficiently. The templates allow you to simply scarf together the ends of the full sheets of plywood, layout the templates, trace a line around the edges and start cutting the hull panels. No lofting required and quite a bit of time saved plotting points and bending sticks.

18’ compact double sea kayak

Some time back, Fred Gasper, from Haslett, Michigan, and I exchanged a few emails about a boat project he wanted to undertake. He was looking to build a double sea kayak so that he and his wife, Kathy, could enjoy paddling activities together. Fred indicated that he had already built several plywood kayaks and was just about finished with his second stripper canoe, so I knew he would not need an extensive guide through the basics of building a larger boat for he and his gal.

You can see in the accompanying photo that Fred has pretty well mastered the art of fine woodworking when it comes to building boats. As a new designer with several boats of my own out in the world, I was looking to get connected to another builder who had the talent and the experience to produce a terrific finished boat. Clearly, after taking a look at some of Fred’s prior projects, I was excited to be combining efforts with his capability.

Fred and Kathy have quite a bit of experience when it comes to taking kayak oriented journeys. They’ve made a few trips to the Pacific Northwest to do just that. They both have a well-developed understanding of what a boat is supposed to do when paddled.

I developed the Lunada Bay design to fill a special niche in the double touring kayak market. The design brief addressed such things as being car-toppable, easily stored in the average garage or basement, able to carry two adults for day paddling and the odd overnighter, highly responsive to turning input and able to track effortlessly. The boat did not need to be able to carry a week’s worth of gear and food or produce a high, sustained speed under paddle, as it was to be a comfortable cruiser for more leisurely outings.

The result was an asymmetric hull design of 18’ LOA with a beam of 28” to be built in a hybrid construction method. Hybrid build style is basically the combination of a marine plywood, multichine hull with a cedar strip built deck. This type of boat takes advantage of the two build styles to offer quick hull construction combined with the natural wood beauty of a stripped deck. It also allows the soft sweeping contours of a stripper on the part of the boat that is most often seen by the paddlers.

In this style, the builder first assembles the hull panels, fillets the hull seams and glass laminates the hull inside and out. He then inserts a series of building stations for the stripped deck process and begins to create the patterns as desired with various colors and species of wood to suit his taste. The hull, itself, provides the strongback form for the stations and soon, the deck is complete and ready to join to the hull with the bulkheads in place.

The cockpit openings are laid-out on the deck surface taking care to measure the Center of Buoyancy of the design to balance the paddling positions in the boat. Once cut out, the cockpits are finished with the construction of the rims and flanges for the paddling sprayskirts. There are probably five recognized methods for cockpit rim fabrication. All of them work and it more or less comes down to how you want the whole thing to look. Something like choosing plaid instead of print for a shirt pattern.

Just last week, Fred and Kathy took their new boat out for a spin on the local lake to see how she’d perform. Fred had been working on the boat, off and on, since mid February. He managed to squeeze-in a trip to the Grand Canyon with Kathy, family obligations, the normal household chores, as well as his regular job, all at the same time. He was more than ready to get the boat on the water. The coming change in the weather probably played an additional role in the urge to go paddling.

I’m pleased to share with you that the boat performed like a star, ticking off the big elements in the design brief while being put through her paces by Fred and Kathy on an overcast, October day in Michigan. Fred just sent me an email and said, “Tracked and turned great with no weathercocking. Don’t think she will need a rudder. We named her “Travelin’ Louise”

This kind of report is pure music to a designer’s ears. I jumped-up from Fred’s email and took my wife and son out to dinner to celebrate. Everything was great, except my wife wouldn’t let me eat the greasy, garlic mushroom burger I really wanted to order. Seems that even though I can design some really nice, trim boats, I have a long way to go to get my own hull form back to my former nice lines.

Fred and Kathy will need to install the backbands, footbraces, carry straps, seats, deck accessories and then finish off Louise with several coats of beautiful, satin varnish before they put her away for the winter. Fred indicates that the finished boat will tip the scales at just over 60 pounds. I’m really looking forward to the reports from their future adventures in “Louise” over the coming years.

As an aside, the name Lunada Bay comes from a local surf and snorkeling location from my youth along the beaches of L.A’s South Bay. Where I come from, Lunada is a Spanish word that loosely translates to a moon lit party on the beach. I have spent many warm summer evenings with friends, cooking freshly caught lobsters and abalone on the beach while a full moon lit the sea. I couldn’t think of a better way to use this boat.

A Superior Weapon for the Outdoorsman

Swamper King & Swamper

One day I was driving around the industrial area near my boat shop and happened to pass the local power boat center. Sitting out front of the store were two, rather homely looking aluminum skiffs that are typically used around Utah to hunt ducks and geese and perform general boating duties for outdoorsmen.

I had never really taken a good look at the type before as I had more pressing matters in front of me trying to finish the build on a sailboat. For some reason, I pulled over to just get an idea as to how these metal boats went together and to understand the shapes that went into the hull. Most folks refer to the form as a Jonboat, although I’ve also seen it as Johnsboat and Flat-Bottomed Skiff, by various other sources.

Jim Michalak’s version of this simple skiff has been a real hit with homebuilders and there’s a bunch of good reasons why that’s so. They’re easy to build, provide hours of trouble free operation with the simplest of outboards and can do just about anything you could ask for a utility boat.

I went home that night and dialed-up the design software and started fooling around with a few ideas as to how I would design one of these boats for my portfolio. The result is that I came up with two versions that are very much alike except that one is a bit longer than the other for added carrying capacity is.

Swamper

This boat is designed to take advantage of the physical properties of the standard, 4×8’ sheet of plywood and make the most of the sheet goods while still imparting a bit of style and form enhancement to the hull shape.

Rather than design a straight, flat-bottomed hull, I chose to give the Swamper a very slight Vee shape for the underwater parts. This gives a somewhat better ride through choppy conditions such as those you would find on any small lake when the wind comes up. If you’ve ever ridden in a flat bottom hull while pushing through small waves and experienced the slamming effect that comes with a flat surface as it hits the oncoming wave, you already know what I mean by this.

The overall length of the boat is 15’5” and the overall beam is just a shade over 55”. The height is 22” along the sides with the gunnel rising from that height in a soft curve, yielding a bow that is only 28.5” above the floor of the boat.

The main components come out of seven total sheets of plywood. The two bottom panels are from 3/8” material and the rest of the boat is from ¼” stock with the exception of the transom which is built from two layers of 3/8” ply. The boat is epoxy filleted and taped on the inside and completely covered in epoxy glass on the outside surfaces. The build style is simple, stitch and glue with one butt joint connection to be made to get the full-length hull panels.

There is a full-length stringer at gunnel level and it is covered with a four-inch wide cap rail completely around the boat with the exception of the transom mounting location for the engine.

Built-in flotation chambers are installed throughout the hull, starting with a big standing platform in the bow that is suitable for fishing. The forward seat can be enclosed with watertight bulkheads as is the far aft seat platform. Two enclosed flotation boxes sit on either side of the engine splashwell. You can swamp this boat and it will not sink.

The flotation chambers can be easily adapted to provide on-board storage if the builder installs watertight hatches or inspection ports.

I feel that the optimal, outboard engine size for this boat would be in the 15-20HP range. It will work just fine with a smaller engine, though, as the boat is quite light. I’m sure somebody will hang something bigger than this, but I’m not recommending it.

The Swamper is perfect for fishing; hunting work related tasks on the water and just plain old fooling around. It can go into some pretty thin water with its draft of just under 7” at 650 pounds of displacement and can easily be setup with oars and a removable center seat for human powered applications.

If you live out in the country and have a good relationship with the local Sheriff, the Swamper will fit snugly between the wheel wells of the standard American pickup. With the tailgate down, you’ll have five feet of boat hanging out, but it is doable. Again, I’m not recommending the practice; just letting you know it can be done… if you’re so inclined.

Normal transport would be with a lightweight trailer, which would allow you to keep the outboard on the boat for short distances. A 15 Hp outboard doesn’t weight too much, but I prefer to see them removed from the transom for transport over long distances.

Swamp King

This boat is very much like the Swamper with virtually the same lines. The biggest differences are the length at 18’, the ability of the boat to carry more weight and the addition of an extra, installed seat with its enclosed flotation volume. With an extra layer of ¼” plywood on the transom, this boat can easily handle a 30-40 HP motor.

The costs to build the Swamp King are slightly greater due to the added plywood for the increased length and some additional trim, structural material as well as extra epoxy and glass.

Even though these are simple boats, they are capable of providing years of wonderful service to the owner/builder with only very minor maintenance. If you have a teenage son or daughter who likes to enjoy outdoor activities with you, this boat would make for a terrific joint project over the winter. Either the Swamper or the Swamp King would make an excellent first boat to hand down when one of them gets old enough to have a boat of their own.

I have developed a new, personal trimaran for small adults and kids called the Solo12. This is a car toppable boat that is meant to sail with no facility for human power other than hauling out the spare canoe paddle and getting with it. The total displacement is 300 lbs. all-up and should tip the scales at about 130 lbs. before getting wet. So, there’s room to wiggle for a wiry dude who wants to tool around in quiet waters and have a blast in a semi-reclining position. Steering is via a pair of pedals and cables to the rudder cheek block, much like a kayak and all the sail controls are fed forward so there’s no need to hike out at all.

The sail area is 56 sq ft. The amas are generously sized to avoid getting out of the cockpit except to hang-out on the beach with friends and have some lunch. Lateral resistance will be provided by a side mounted leeboard on a swivel mount. This will give the boat plenty of upwind lift while being a safety oriented feature that kicks up and out of the way for beaching, or encountering underwater obstacles

The aka tubes are aircraft aluminum and will be segmented with the same spring pins and fitted ferrules you see on take-a-part paddles, so that the amas will reconnect right up next to the main hull for transport and storage. A very compact unit for putting on the roof of your car and going off to the beach, or lake, for some fun.

The build is 3mm marine ply with a full layer of glass outside and taped joints inside. Easy to build, easy to move around the launch site and perfect for learning to sail with little kids as they can sit between your legs and learn how things work. Later, the same kids can take the boat out on their own and there will be no fear of them tipping over unless a tornado hits the area.

There is a companion model at 14′ LOA for slightly larger sailors, all within the car-topping attitude that this boat represents. The SOLO 14 has an optional ama design that allows the removal of the leeboard as the lateral resistance will come from the underwater fin shapes of the amas. This keeps the stuff hanging in the water to a minimum while still allowing a decent performance capability. fewer moving parts will mean simpler maintenance and less stuff to possibly break while out sailing. The rendering above shows the finned amas in place.

Sports Car Performance on the Water

Over the past couple of years, I have taken a break from my boat design work. During that time, I’ve been able to reassess my connection to the craft. The last boat I designed was the Europa 20, which is a trimaran meant for vertical strip foam construction with sandwich style, infused epoxy/glass laminates inside and out. The Europa is a boat for very fast day sailing with a very light hull and a very big rig. A boat that is not for everyone, to be sure, as it requires a level of skill that the average guy does not typically cultivate in the course of experiencing their recreational boating interests.

In stepping away from the larger, more powerful beach type multihulls, I came around to the desire to produce a smaller, very quick and sensitive boat that would appeal to recreational sailors and not just those guys who want to blast around with their hair on fire (though I do suspect that in the right hands, this boat will do just that). The new design had to be easy to build with standard, marine plywood/epoxy/glass techniques that did not rely on exotic layups with spendy carbon cloth. (Well, maybe the carbon will sneak in there a bit on the beams for the guys who want to play with a bigger rig)

Looking long and hard at the smaller skiff-like hull designs I had done before, such as the Montage, I decided to draw the new boat in that same general size, but with a very different approach when it comes to how the boat achieves its performance potential. Where the Montage has a relatively spacious cockpit capable of taking on a couple of adults, (or a parent and a couple of smaller kids) the new, Corsica 15R trimaran would be for one adult (or accomplished kid) designed solely for a unique, one-up sailing experience within the small beach multihull genre.

Much like a performance dinghy, the Montage has a wide, flat sailing surface conducive to the planing of the main hull. It’s more like an outrigger supported dinghy in that regard, than it is a trimaran. Certainly, the Montage fits within a grey area when it comes to defining nomenclature. The Corsica 15R, however, would be very much like other high performance trimarans with very slender, easily driven hulls that have the potential to achieve boat speeds well beyond the typical displacement design. There is no main hull planing function going on with the Corsica 15R. It is all about pure, straightforward achievable speed via well-known multihull design thinking.

As a result, the boat has minimized clutter when it comes to excessive high-tech trickery. With that approach, the Corsica 15R is also going to be a boat that has much lower maintenance requirements in order to keep it in top sailing condition, as well as a much lower realized cost to get it on the water and ready to sail.

If you are into cars, as I am, then think in terms of a nicely pumped, Mazda Miata, type of boat that would be a cool, weekend canyon racer for one person. A boat that could blast around the local waters in a good breeze and give chase to other small, fast, multihulls being sailed by crews of two.

The result of this conceptualizing process is the Corsica 15R. The C15R is a boat of modest, marine plywood build techniques and is very light weight for its generous sail area. With this boat, the normal sailing position would be the skipper, semi-reclined within the main hull, driving his machine like an F1 Grand Prix car. In this configuration, the boat is designed to utilize foot pedals for steering, leaving the hands free to work the sheets. But, that’s not the only way to sail this boat. Owners who wish to sail in a more conventional multihull style, can sit-up out of the cockpit and onto the main hull cockpit gunnel, or even the trampoline surfaces all the way out to the ama, where they will steer with a tiller extension.

A construction style in multichine, 4 mm marine plywood, allows the boat to be assembled in a well-understood fashion that will go together quickly. With a subtle placement of minimal stringers and sufficient bulkheads, the C15R becomes a strong main hull shell that can absorb the loads from its sizeable rig, turning the power of the sails into forward thrust in the water.

There is no fully enclosed transom on the vaka hull. The cockpit deck is slanted gently down and aft for automatic self-draining, such as is seen in sport dinghies and larger race boats. A collection of bulkheads under the cockpit deck provide structural support and watertight compartments ensuring that the boat will not likely sink even if large sections of the bottom are torn out from an underwater hazard while smoking along in a gin clear lagoon.

The demounted boat can be assembled easily by one person. The gently gull-winged akas are built with a glassed box beam core. The inboard ends of the akas slide into tapered sockets in the main hull and are levered in place with stainless waterstays to make ready for sailing. This, tapered socket technique prevents binding while assembling the boat, while providing a solid, hassle-free and weight minimized demounting system. The leading edges of the akas are smoothly shaped foam blocks that are glassed onto the box beam to provide an aero component, as well as creating reduced drag from waves and spray. The akas are hard fastened to the amas as a complete assembly that is easily removable from the vaka hull. The trampolines stay mounted to the akas and amas for transport and only have to be hooked and tensioned to the main hull during assembly.

The mast is a stick from a Hobie 16. I specify the addition of a set of spreaders from the Hobie 18 mast to stiffen up the H16 mast to handle the additional righting moment generated by the Corsica design. Naturally, I’d prefer to see fresh sails in something like fully battened, Pentex laminate, but builders on a tight budget could also work with a loft service to tweak a reasonably fresh Hobie 16 main and jib and do just fine. The addition of reefing points on the main are strongly suggested, as well as the use of furlers for the jib and spinnaker/screacher. For those who desire fresh sails for this boat, I would recommend the folks at Whirlwind sails in San Diego, California. http://www.whirlwindsails.com/

A removable carbon prodder sets the tone at the front end of the boat. The stick originates as a carbon windsurf mast, so it is easily found on the used market and equally replaceable, should it get poked into an unyielding environment. For trailering, the sprit unpins, slides out of its socket and is stowed in the cockpit for transport and storage.

Corsica 15R Specifcations

LOA 14’ 11” (4.54 m)

BOA 13’ (3.96 m)

Displacement 650 lbs. (294.8 kg.)

Sail Area (upwind) 218 sq. ft. (16.17 sq. m)

Spin 142 sq. ft. (13.19 sq. m)

Mast Length 26’ (7.62 m)

Draft (board up) 1’ (.3 m)

Draft (board down) 42” (1.07 m)

The mast is raised by the traditional beach cat method of physically lifting the mast with the base pinned to the mast step, or by utilizing the long daggerboard in its trunk as a form of a gin pole. A forward hoisting line is led over a pair of sheaves at the top of the daggerboard and down to the hand cranked winch on the trailer. Mechanical leverage quickly raises the mast so that the forestay can be fastened to the bow, stepping the mast securely. You can see a few photos of the process at Brent’s L7 trimaran site:

I chose to not go with tricked-out, curved lifting foils in the amas due to construction complexity and added cost for the builder. Foils of this type are hard to build correctly by hand, as are the needed curved trunks in which they slide. Instead, the boat is equipped with a daggerboard that is inserted through the deck of the main hull in front of the mast which angles aft to exit the hull below the waterline. A daggerboard and trunk of this type are much simpler forms to build and orient in the hull. It is also just one main foil, where lifting foils need to be made in pairs, one for each ama. Lifting foils also need complex control mechanisms to retract and deploy the foils and they have to work from the cockpit remotely with the foils mounted way out in the amas. The needed controls are an interesting problem when the boat is 13’ in width and the driver is semi-reclined in the main hull.

Note: I’m not against an owner who might want to experiment with foiling for this boat, even if it is just foil assist and not full flying. It would require a lifting t-foil style rudder and twin Bruce style foils in the amas, or, if a person is really accomplished as a composites builder, they could make a pair of matching c-foils for the ama. The owner just needs to know what level of additional work is involved and at what skill level they need to perform in order to get the desired result.

If you are on a budget, the rudder and headstock from a Hobie 16 will work just fine for the Corsica with some mods to the tiller. The more deluxe, Rudder 25 system from Dotan will also work well, should you have the coin. http://www.dotan.com/ If you plan on pushing the boat hard, then a longer blade will be required, or you can get yourself invested in the process of putting a rudder on each ama and have stunning control at your finger tips. On the down side, that change will cost you a bit out of your pocket and at the launch ramp in setup time… though I can see a nifty rig with light alu tubing and the use of snap buttons as a cool solution.

The Corsica 15R will be a light boat built from familiar materials. It should be a fairly simple building experience for the owner and will fit comfortably into any typical garage space, making it easy to find a building location. It will quickly assemble for sailing and be hassle free with minimal maintenance required to keep it in top form. It can be towed behind any compact car on a typical beach cat trailer and when demounted for travel, is road legal anywhere in the world. On the water, this boat should be quite quick and behave with predictable, pin-point sailing manners. With the skipper slung comfortably in his reclined cockpit seat, he will be decently protected from the effects of the weather and sea state while tearing around his local waters.

Dual Mirage Drive powered, two person launch

Some time back, I encountered an ex-pat American, now living in Melbourne, Australia, by the name of Mack Horton. Mack wanted to build a two-person boat for cruising the harbor and waterways of his hometown, Melbourne. He was looking to propel his boat with a twin setup of the wonderfully innovative Hobie Mirage drive designed by Greg Ketterman. I really liked that idea as I had already done a few different boats that were Mirage capable, but they were all solo boats. This design concept opened a new door for me, as it would allow me work out the balance and weight issues for a twin drive and once built, I could also discover how much more speed potential might be available beyond a solo drive.

I had a hull in mind from my portfolio that would need to be “massaged” just a bit to get the form stability and low-speed performance for which I was looking. The boat had to be able to handle potentially large boat wakes and small chop of the open regions of the harbor and still be easily driven by human leg power.

I was looking to achieve some of the lines of a classic launch with reasonably low windage and yet, enough freeboard to ward off the possible conditions. Surprisingly, the hull form came directly from a previous boat shown at the Duckworks Magazine, the A18, canoe/trimaran.

The A18 hull had a very strong bias towards higher speed potential with only a nod to being driven at slower speeds, so a slimming process had to take place in the forward and aft sections of the hull. Likewise, the beam of the hull was pulled out some to give the boat a solid degree of form stability so it could ride the wakes of passing freighters in the harbor when taken abeam.

I sent the plans off to Mack and he promptly got to work on the boat at his favorite spot for boatbuilding, the Melbourne Wooden Boat Center

Mack has now finished the boat and has had it out on many outings. He’s learning a lot about boat trim and optimal placement of the heavier pedaler for best performance and handling. Besides the still photos showing the boat on the water, Mack has also provided a pair of video clips showing the boat underway.

Clearly, Mack’s Strider, Ripple, is showing itself to be a pretty fast boat when being propelled by two average people. This is being done from a semi-reclining position with hands free, while enjoying the sights in the Melbourne harbor and adjacent waterways. Here is a link to an article I wrote for Duckworks Magazine that shows the GPS track and speed data achieved by the Strider design: http://duckworksmagazine.com/08/reports/feb-mar/index.htm This is pretty heady stuff for a human-powered vessel intended for casual cruising and not blistering speed.

Mack reports that one of the ubiquitous dinner cruise boats, that you see in just about every harbor of the world these days, pulled alongside and challenged both he and his friend, Justine, to a little race. Off they went with Ripple easily leaving the cruise boat in the dust. Let’s overlook the fact that powered cruise vessels of this type have strict wake generating spped limitations…

Later, as shown in the video clip, Mack and Justine took-on a fully crewed Dragon boat. Dragon boats measure 40 feet in length, 4 feet in width and carry 20 paddlers, 1 drummer, and 1 steers person. On average, these boats weigh 500 pounds. Understandably, Ripple could not quite match the speed of the Dragon boat with twice the waterline length and 20 paddlers. Perhaps there could be a triple version of the Strider in the future? One that is longer, more slender and much, much faster.

The Strider design calls for a very straight forward stitch and glue build method in 4mm marine plywood with glass/epoxy laminates inside and out. The twin Mirage trunks sit cleanly in the hull allowing for a comfortable seating arrangement for two persons and their day pedaling “stuff” such as binoculars, cameras, food, drink, blankets, etc.

In the right environment, the boat could easily be used for overnight camping as well, as there is plenty of displacement capacity for more gear, should the owners wish to use their boat in that fashion.

I expect to see these boats being equipped with Bimini covers and small forward dodgers. The interior hull sides will probably be lined with neat rows of mesh bags to storage of the small things that make for a really nice time on the water, such as: sunscreen, lip balm, mosquito repellant, drinking water, snacks, camera, VHF radio, GPS, etc.

Maybe you have a cabin/cottage on a lake where the general store is across the water, but a short distance, but to walk, it would take an hour to get there. Strider is an excellent, human powered boat for a trip like that. An enterprising person could equip her with an all-weather set of side panels to mount under the Bimini edges, allowing trips to the market in any conditions, short of a full-on gale. (Check out the last video clip above)

The boat is cartoppable, much like a large canoe would be, but I’d advise the person doing the loading be reasonably fit and/or have a really sweet loading system, or technique, as the boat does weigh right around 70 pounds without the Mirage drives in place.

Mack has kindly supplied some very interesting speed marks for the boat that were confirmed with a Garmin Edge 305 GPS with wireless heart rate and cadence monitors.

Highest speed attained with two pedalers…… 7.2 knots

Highest speed with one pedaler………………… 5.7 knots

Average speed for one hour w/ two………….. 4.8 knots

Average speed for two hours w/ one…………. 3.9 knots

Turning circle for the Strider is 33’

These figures run pretty much spot on with my estimations. They also indicate that the hull has gotten to its, “not gonna go there” speed limit and will be pushing uphill on its bow wave from that point on.

While underway in Strider #1, “Ripple”, it is not unusual to be hailed from dockside and beasked, “What is it?”, “How does it work?”, “How much does it cost?”, and his favorite… “It looks like it has an engine!”

Response has been very positive from athletes, because it’s fast… and from non-water type folks because Strider is stable, comfortable, dry and “not scary”.

One of the reasons that Strider is so stable is due to the recreationally respectful beam of the hull. I’m working on a much faster version of the Strider design concept, which should pretty much take the Mirage drive out to its theoretical top speed limit.

All in all, Strider is a really fun and stable human powered vessel designed for recreational pursuits by two people. It has the classic look and feel of a traditional launch to it while underway and can easily power-up to get out of the way of oncoming traffic in a crowded harbor, or lake setting.

STYLISH CRUISING FOR TWO

The A64 originally appeared as a design article on the pages of Duckworks Magazine back in 2006 (yeah, really!). When the boat was shown at the time, it was designed as a request from a friend of mine for he and his wife.

Since that time, I have revisited the design and taken a fresh look at the boat, its potential and the wide range of uses it might see while in use. There are more than a few revisions to the design in this iteration and I am very happy with the outcome.

While it would seem from outward appearances, that this boat would be a perfect fit with a modern rig like a Marconi, the truth is, I’ve been playing around with more traditional setups for the A64. Even though the A64 is capable of some pretty quick sailing, I was looking for a bit less of a hotrod, while very much wanting versatility in rig setup and handling. The boat has had its displacement potential enhanced just a bit so that it could easily carry the gear for a well-equipped camping and cruising scenario. I see the boat being used for long, extended weekends on the water, so the extra capacity is a welcome change.

Much of the inspiration for the A64 is due to the design of Joe Henry’s truly sweet, Flaquita tacking outrigger. I’d always liked the compact beauty and well thought-out utility of Flaquita and it has remained so, even after the new revisions. There are still a small collection of images of Flaquita on the Web if you are Google adept.

It’s no secret that designers have been pilfering each other’s design cues for as long as man has been building boats. Far from being offended by the process, I find that it’s the very essence of the pilfering that allows for new ideas to be incorporated. These incorporated changes, in turn, have the potential to improve the usefulness, the performance and the strength of the boats so that everyone benefits.

Vaka Hull

The revised vaka hull for the A64 is quite bit narrower than the initial design. It also draws more water with increased rocker. The initial boat was done to a very specific design brief that specified very thin water capability and a fairly short paddle length to the water. The new boat is basically a narrow hulled, multi-chined canoe form that is designed to optimize the displacement requirements while providing the least amount of wetted surface. The prismatic coefficient of a normal canoe hull has been changed to .56 to allow the boat to accelerate to speed comfortably and hold its speed with little effort. Paddling, while still comfortably possible, will probably be replaced by a small, 2 HP outboard engine… something like a Honda 2hp four stroke would be ideal. Close quarters maneuvering will likely be done with a paddle as paddles are truly effective when the movement space is tight.

I drew the boat to have a typical, multihull trampoline surface on the ama side of the vaka hull and a non-typical trampoline surface on the off side that was inspired by Flaquita. To form a mental picture of the tramp surface, picture one of those sling chairs you might have had when you were a young college dude. Simply, it’s a loose trampoline cloth slung from an outboard rail back to the hull gunnel with enough slack to provide a seat for the crew when they need to hike out. The rack is angled up to provide the backrest component of the seat as well as give water clearance when the boat is heeled to the offside. The tramp surfaces can be rolled-back away from the canoe hull gunnel to allow for traditional paddling. Take a look at the renderings to get the complete picture.

The vaka hull is decked to enclose the bow area back to the forward aka beam as well as the aft section behind the open crew compartment. A somewhat traditional cockpit rim is specified for the central opening so that the owners can install a large spray skirt covering. This rim will keep a lot of the wave wash out of the boat under sail and paddle, as well as increase structural integrity. The fore and aft decked sections provide for watertight storage as well as flotation, should the boat be swamped or capsized. Additional flotation is provided by the single large ama, as well as the new, safety ama. This boat is not going to sink, should some major operator error get it upside down. You may lose any unattached belongings, but the boat will not sink (well, short of driving it on a reef at speed, holing all the flotation chambers)

Ama Design

The redesigned ama reflects my current thinking for a stitch and glue built form of this type. I have increased the volume for more of a heeling resistance margin. The ama has also been reshaped to more efficiently shed water from the deck, should it become immersed completely while being driven hard. Where the previous ama had a large flat deck surface, the new one has angular shapes that bevel into a much narrower top deck. This will allow the ama to drive back to the surface and give a huge new margin of safety to the boat when sailed hard.

The form is still very full, as well as deep in the forward sections, putting the flotation where it is needed the most. The bottom profile of the ama tapers up and away from the water as it moves aft to maintain the least amount of wetted surface for the ama as it is pressed. The new ama is a high efficiency design with just under 100% displacement buoyancy of 1029 pounds when submerged to its deck. When coupled with the length of the aka beam, the ama volume represents a considerable amount of righting moment.

Most single outrigger designs will be parked with the canoe hull adjacent to another boat or dock. The generous ama buoyancy of the A64 allows it to be maneuvered so that the ama is right up alongside a dock and the crew can easily walk across the trampoline to go ashore. Two, full grown adults can stand on top of the ama and not come close to submerging the form.

As an alternate to this type of docking strategy, the off-side, safety ama, is hinged, allowing it to be swung up and over the vaka hull. This allows the boat to be drawn right up next to the dock for direct entry to the vaka hull.

Curved Aka Beams

There are two methods for building the aka beams. The simplest is to laminate 3mm (1/8″) hardwood strips on a form, glued together with epoxy. The builder then glasses the beam, fills the weave and varnishes to high gloss to reveal the beauty of the wood beneath.

If you wanted to go all-out, you could make an easily constructed, epoxy/glass, box beam structure. The leading edges of the box beam would be further shaped in foam to give the beam an aero/hydrodynamic form as presented to the wind and waves. The entire form is then glassed for a finished beam and then painted as desired.

The akas attach to the canoe hull with simple cinch buckle straps much like those used to tie-down boats to roof racks. I have found this system to be extremely dependable, economical and the straps are very simple to replace if one breaks or is misplaced.

If the A64 is trailered, the main ama remains mounted to the hull and the offside ama, which is hinged, swimgs up and over the vaka. Transport width for the boat in this configuration is just under 8’ and well within legal limits. This makes for an incredibly fast setup and take-down at the launch ramp. The only work involved is in stepping the rigs, mounting the rudder and attaching the offside hiking tramp.

The Rig

The base design specifies a balanced Lug rigged yawl. The main mast will be rigged with a 70 sq. ft. sail and the mizzen will fill-out at 33 sq. ft. The balanced Lug provides simplicity in rigging and reefing and is surprisingly powerful, stows inside the hull with ease and could also be built quickly and economically in poly tarp, if the owner is so inclined and finances dictate.

Alternate Rig Solutions

The boat has also been drawn as a 131 sq. ft. Gunter yawl, if the desire for more performance is there. In fact, there are many rig configurations that could be run on this boat and I’d like to see builders experiment a bit to find the magic for their own adventures.

For those who seek a bit more in their sailing adventures, I have also drawn the A64 with a 156 sq. ft. Marconi yawl rig. Along with this rig, there is an option for a 124 sq. ft. Gennaker flown from the forward mast. With the spinnaker flying, one could expect that this boat will be quite quick in favorable, offwind conditions, capable of covering a lot of distance in a short time.

The Foils

The vaka hull will be equipped with a leeboard that is mounted to the port side of the hull. It will rotate for shallow water and be of a planform and foil section that will provide the best balance of lift and minimized drag for the sailing speeds of the boat. Typically, I like my leeboards on boats of this type to be NACA 0009 sections.

Likewise, the rudder’s characteristics will match the needs of the boat’s performance and it will be able to flip-up when it contacts underwater obstacles, or is beached while down. I do this with a simple bungee on the leading edge of the rudder, well above the waterline. The bungee holds the rudder down with sufficient force to overcome water pressure while sailing, but it easily stretches, allowing the rudder to swing up and aft if the blade contacts anything more substantial. The rudder foil will be a NACA 0012 section, to maximize control and minimize stall for low speed maneuvering.

The A64 will be very easy to build, it will be very light weight for its size and, therefore, quite easily driven in even the lightest of winds. The boat will carry a sizeable load for a very long weekend on the water. I wouldn’t be surprised at all if a couple of adventure cruisers could pack enough stuff on board for an entire week away from a source of supply.

It can be sailed comfortably in the thinnest of water and if the wind dies, this boat can be effortlessly propelled with traditional paddles for reasonable distances… or the crew can simply fire-up the Honda and go wherever their gas tank allows them. Perhaps this isn’t a real big issue for a lot of cruising boaters, but the A64 will be capable of surprising speed under sail. That will be especially true if equipped with the larger sail rig.

Adaptable, Modular Design

As a last little bit, to put an element of curiosity into the design package, there is a very nice folding trimaran with a comfortable solo cabin that is derived from this same vaka hull design that I will introduce in the very near future called the A21.

Any and all comments, or questions, about this design or the upcoming A21 are encouraged.

I’ve been getting a significant number of inquiries for the power version of my Gato Especial sailing cat. I let it slip out, some time back, that there would be an engine driven version coming along, but time got away from me and so, the project sat idling on the design table.

I’m kind of drawn to cars and boats that can solve a host of utility needs, as well as provide a comfortable, transportation experience. I’m about to sell my venerable Toyota Landcruiser and get myself into something that makes a lot more sense when it comes to utility and fuel efficiency. As a result, I began to think of a motorized version of the Gato platform as a Crossover/SUV type of vehicle with a big interior volume aft of the helm station and truly fuel-efficient engines to complete the picture.

The new boat would have a stand-up position for the driver with a sliding, deck-mounted seat that would allow the skipper to sit while steering. There would be a huge deck surface behind the helm for all sorts of seating and/or gear carrying options. The new boat would have a tailgate/liftgate setup for ease of loading. The new design would have a big storage space forward of the helm for the odds and ends that always end-up on a boat. Power for the initial design would be from a pair of four stroke outboard engines for redundancy, as well as beneficial weight distribution.

On a personal level, I am attracted to design concepts that deliver a responsible set of solutions for this new economic reality in which we all live. I like the term, Crossover, which is openly lifted from the automotive industry, as it touches on the realities we will all face in the coming years. We are headed to a time in which our vehicles will need to do more than just give us a sedan in which to cruise around, or a truck to do our dirty jobs.

In the world of cars, the Crossover approach has created vehicles that live in the niche right between the heavier, clunkier, SUV’s and the typical, everyday passenger car. Similarly, with this new design, I was looking to take the slot right between the generously proportioned sport cruisers you see at marinas all over the world and something like a cleanly drawn work boat. I wanted some of the people driven touches of scale and fit/finish, while being able to morph from one working task to another as a truly useful, all-around watercraft.

The result would be my take on what a boat should look like which is much more fuel-efficient and less expensive to build and transport. It would provide a very high degree of utility and, of course, it would need to be wrapped in an aesthetically pleasing package.

The aesthetic, design component is pretty much a subjective thing, but the fuel-efficient aspects are a design process that combines easily driven lightweight hulls, drive systems with high economy for delivered horsepower and a significantly reduced aero drag signature allowing the boat to just slip through the air.

I’m of the opinion that I have reached all the basic design criteria with this new design, The Largo.

Yeah, sure there’s a distinct connection to the Bond films, Thunderball and Never Say Never Again, with the bad guys both being named Largo. Beyond that, Largo is also a direct take on the ’48 Film Noir thriller with Bogey, Bacall and Edward G. Robinson. It is also, the well-known island in the Florida Keys where boating adventures await in every direction and one of my favorite adventure boating events, The Watertribe Everglades Challenge maintains its finish line.

Largo Specifications

LOA 21′
BOA (trailer legal) 8′ 6″
Height 6′ 5″
Displacement 2000 lbs.

Suggested engine package is Twin 9.9 hp four stroke outboards. It may not seem like it from the renderings, but plenty of interior volume has been worked into the design to allow full movement of the engines from side to side

The aft cabin space of the trimmed-down version will have the potential for a huge, manual, slide-back sunroof for a full open-air effect in the main cabin volume, as well as large side openings for breeze and visibility. The side openings can be fitted with removable, semi-structural soft windows for better streamlining and also for inclement weather.

Way back at the aft end, the boat has a floor level, drop-down tailgate, as well as a glassed, liftgate. I see this as a utility benefit when the boat is beached, bow out, in a marina slip. The tailgate will allow easy loading of gear and anything else that might be shoved in the back of this boat while it is still on the trailer. It will also give a chance to sit on the tailgate and hang out. The entire hardtop can also be removed for a full-on waterborne convertible. Or, if you like, a pick-up truck for the waterfront that can haul a whole bunch of oddly shaped objects, should you have a need for that kind of utility with friends while enjoying a sandwich or cold beverage.

The suggested engine package is based on need. If the owner wants to cruise with high efficiency and still be able to bang out 11-12 knots when he likes, then a pair of Yamaha Hi-Thrust 9.9 hp engines will do the trick. The engine setup can be equipped with remote starting, steering and power engine tilt. They both have pretty healthy alternators to keep any onboard electrics going, so lighting, navigation and radio systems can be easily powered-up.

Cutting edge enthusiasts will ditch the outboards and equip the boat with a bank of batteries under the deck in each hull and a pair of powerful electric motors that drive a set of matched, counter-rotating props. As an alternative to the twin outboards, this boat, so equipped, will silently cruise with a pretty decent range and be able to go to full power instantly whenever the owner wants the buzz of the electric drive potential.

The hulls of the Largo are exactly the same as those of the Gato Especial sailing cat. They are 10-1 in Length to Beam ratio at the waterline and will be very easily driven while still providing a respectable displacement payload. The is a spray chine on the inside and outside of each hull to direct wave action away from the boat while underway, as well as reduce drag on the hull. At cruising speed, a small amount of hull lift is also a side benefit of the spray chines.

The aft end of the hull bottoms is relieved with a slot to allow engine placement forward of the typical transom mounting and to allow the power tilt capability to raise the props well clear of the hull bottom for beaching and trailer loading/unloading. Moving the engines forward adjusts the balance point of the boat forward and helps with handling and pitching moments. It also puts the engines inside of sound deadening boxes, so the overall noise level is reduced while underway. Cruise the harbor on a warm summer evening with soft music playing on the surround sound system and you can really hear the soft music.

Bridgedeck clearance between the hulls is a generous 17″, so wave slap under the main deck will be kept to a minimum. This raises the overall comfort level of the boat, which is especially nice on a longer trip.

The large deck space inside the boat will make for a spacious camping environment, gear hauling space, or just about anything else you can think of doing with a boat that is this versatile. The tailgate opens to a generous 49″ width, allowing the owner to load full sheets of plywood right through the back of the boat without leaning them up on edge.

The hull volumes below the main deck can also be used for the storage of fuel, batteries, water tanks, anchor, rode, etc. It’s always a good thing to keep the heaviest items on a boat as low as possible to enhance stability and improve ride. The space in front of the main forward bulkhead can be accessed via a large hatch. This is an excellent location for lighter weight storage needs such a sleeping bags, tents, clothing, etc.

A good friend asked if the boat could be equipped with a drop-down front ramp and a walk through windscreen so that the Largo could be driven right up onto the beach to unload through the bow. The answer is Yes… certainly can accommodate that feature with a few changes to the forward structure.

Clearly, the Largo is a boat with a generous latitude of use potential, it draws design cues from a pretty diverse group of sources and sets a new standard for home built power boats with a decided edge towards fuel economy and responsible boating.